/**
 * Copyright (C) 2002-2015   The FreeCol Team
 * <p>
 * This file is part of FreeCol.
 * <p>
 * FreeCol is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 * <p>
 * FreeCol is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * <p>
 * You should have received a copy of the GNU General Public License
 * along with FreeCol.  If not, see <http://www.gnu.org/licenses/>.
 */

package net.sf.freecol.common.model;

import net.sf.freecol.common.i18n.Messages;

import static net.sf.freecol.common.util.CollectionUtils.*;
import static net.sf.freecol.common.util.StringUtils.*;


/**
 * A measure of the tension between nations.
 */
public class Tension implements Named
{

    // Minimum possible tension value.
    public static final int TENSION_MIN = 0;
    // Maximum possible tension value.
    public static final int TENSION_MAX = Level.HATEFUL.limit + 100;
    // Hysteresis value
    public static final int DELTA = 10;
    // Unit destroyed, etc
    public static final int TENSION_ADD_MINOR = 100;
    // Unit destroyed in a Settlement, etc
    public static final int TENSION_ADD_NORMAL = 200;
    // Unit destroyed in a capital, etc
    public static final int TENSION_ADD_MAJOR = 300;
    // Grab land without paying
    public static final int TENSION_ADD_LAND_TAKEN = 200;
    // Unit destroyed
    public static final int TENSION_ADD_UNIT_DESTROYED = 400;
    // Settlement attacked
    public static final int TENSION_ADD_SETTLEMENT_ATTACKED = 500;
    // Capital attacked
    public static final int TENSION_ADD_CAPITAL_ATTACKED = 600;
    // War inciter
    public static final int TENSION_ADD_WAR_INCITER = 250;

    // Tension modifiers
    public static final int CONTACT_MODIFIER = 0;
    public static final int ALLIANCE_MODIFIER = - 500;
    public static final int DROP_ALLIANCE_MODIFIER = 200;
    public static final int PEACE_TREATY_MODIFIER = - 250;
    public static final int CEASE_FIRE_MODIFIER = - 250;
    public static final int WAR_MODIFIER = Level.HATEFUL.limit;
    public static final int RESUME_WAR_MODIFIER = 750; // War from cease fire

    /** Tension level to set when surrendering. */
    public static final int SURRENDERED
            = ( Level.CONTENT.limit + Level.HAPPY.limit ) / 2;

    /**
     * Constants for describing alarm levels.
     */
    public static enum Level
    {
        HAPPY( 100 ),
        CONTENT( 600 ),
        DISPLEASED( 700 ),
        ANGRY( 800 ),
        HATEFUL( 1000 );

        private final int limit;

        Level( int limit )
        {
            this.limit = limit;
        }

        public int getLimit( )
        {
            return limit;
        }

        /**
         * Get a message key for the level.
         *
         * @return A message key.
         */
        public String getKey( )
        {
            return getEnumKey( this );
        }
    }

    private int value;


    /**
     * Create the default tension.
     */
    public Tension( )
    {
        setValue( Level.HAPPY.getLimit( ) );
    }

    /**
     * Create tension at a specified level.
     *
     * @param newTension The level of tension.
     */
    public Tension( int newTension )
    {
        setValue( newTension );
    }


    /**
     * Get the current tension value.
     *
     * @return The value of this <code>Tension</code>.
     */
    public final int getValue( )
    {
        return this.value;
    }

    /**
     * Sets the current tension value.
     *
     * @param newValue The new value of the tension.
     */
    public final void setValue( int newValue )
    {
        if ( newValue < TENSION_MIN )
        {
            value = TENSION_MIN;
        }
        else if ( newValue > TENSION_MAX )
        {
            value = TENSION_MAX;
        }
        else
        {
            value = newValue;
        }
    }

    /**
     * Get the current tension level.
     *
     * @return The current level.
     */
    public final Level getLevel( )
    {
        return find( Level.values( ), level -> value <= level.getLimit( ),
                     Level.HATEFUL );
    }

    /**
     * Modify the tension by the given amount.
     *
     * @param newTension The amount to modify tension by.
     */
    public final void modify( int newTension )
    {
        setValue( value + newTension );
    }

    /**
     * Get the stem key.
     *
     * @return The tension stem key.
     */
    public String getKey( )
    {
        return "tension." + getLevel( ).getKey( );
    }

    // Implement Named

    /**
     * {@inheritDoc}
     */
    public String getNameKey( )
    {
        return Messages.nameKey( "model." + getKey( ) );
    }

    // Override Object

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString( )
    {
        return getLevel( ).toString( );
    }
}
